Level Streaming Advice needed


I have a map pretty much worked out on a basic level (Heightmap, 8129x8129).

If i would go for level streaming, is it advicable to go ahead and make additional levels for specific zones and adding levels for foliage / Rocks for those Zones?

To be more specific i would go ahead and split the whole map in12 Zones and give each zone a seperate level for foliage/rocks.

what would you guys advice?

Edit: Oh and on that note, do i need a camera for each zone? or is the camera only needed once for activating streaming at all (watched it in a tut by brick whut)